1. Field of the Invention
The present invention relates to an apparatus for film deposition, and in particular relates to an apparatus for chemical bath deposition.
2. Description of the Related Art
Development in the solar cell industry is driven by global environmental concerns and rising raw material prices. Among the various solar cells developed, dye-sensitized solar cell (DSSC) is advantageous as it can be fabricated with relatively lower costs due to its simpler fabrication process and ability for large area fabrication.
In a solar cell, a buffer layer plays an important role, because it is used as an n-type material and it protects the absorption layer of the solar cell. Therefore, it is important to fabricate a high quality buffer layer to improve the photoelectric conversion efficiency of solar cells.
Techniques for deposition of the buffer layer include: sputtering, vacuum evaporation, chemical bath deposition (CBD), spray pyrolysis, in which chemical bath deposition (CBD), is a widely used method due to its simple process and required low cost equipment. However, the conventional CBD process consumes a large amount of chemicals, and results in a large amount of waste.
FIG. 1 shows a conventional chemical bath deposition (CBD) apparatus which comprises a crucible 11, top cover 12 and a plurality of substrates 13 for film deposition. Because the substrates 13 are vertically disposed in the crucible 11, the upper portion and the lower portion of the substrate 13 have a non-uniform film thickness. Additionally, a large amount of solution for film deposition is needed, and after the deposition process, washing of the crucible 11 is needed.
Thus, there is a need to provide a chemical bath bat-deposition apparatus with a simple process, using fewer chemicals.